Mobile terminals, which have become indispensable communication and entertainment tools in work and life at present, are being developed to become intelligent with large screens. At present, smart phones with large screens and tablet computers are being used more and more widely, and have shown a sign of invading and occupying the market of Personal Computers (PC). Therefore, there is no doubt that device manufacturers are attaching importance to and invest on mobile terminals.
On the other hand, however, the impact caused by radiation of mobile terminals on human bodies also causes attention of various countries, organizations and consumers. At present, the result of a Specific Absorption Rate (SAR) test is a very important index in certification of mobile terminals, especially tablet computer products, and an impact of these kinds of products on a human body is largely reduced by the constraint of an SAR on the radiation performance of the products. Currently, an SAR reducing method is used in the products. The proximity of the human body is detected by an SAR reducing antenna, i.e. a sensor, so as to control and reduce the output power of the mobile terminal. The processing method above, which is generally applied in a tablet computer, and will be also used in a mobile phone sooner or later as the size of the mobile phone is becoming close to that of the tablet computer, is advantageous in that a degree of reduction is flexible and controllable, but has a disadvantage that the sensibility (a sensing range) for the SAR reducing antenna to sense the proximity of the human body limits the change sensibility of the radiation power of the mobile terminal, thus resulting in erroneous judgment, e.g., the sensor has started working when the human body has not been close to the terminal, or the sensor has not started working when the human body has been close to the terminal.